In U.S. Pat. No. 4,124,470 there is described an automatic apparatus for zone or density gradient electrophoresis. The apparatus utilizes a turntable onto which are loaded empty electrophoresis tubes which are filled in serial fashion with sample and electrophoresis medium utilizing an automatic diluter. Each of the tubes has conductive means at both ends and when voltage is supplied an electrophoretic pattern is produced in the tubes. The turntable transports the tubes from the loading station to a scanning station while the electrophoresis separation is proceeding. The electrophoretic patterns are scanned by means of an optical probe which is dipped into the electrophoresis tube without disturbing the bands. Other types of protein (isoenzymes) are measured after dispensing of a selective reagent.
A tube gel electrophoresis device is described in U.S. Pat. No. 4,048,049 which comprises a number of concentrically mounted gel tubes. The tubes extend between an upper buffer chamber and a lower buffer chamber. The lower buffer chamber is operatively connected to a cooling core so as to provide heat transfer during the electrophoresis. An advantage ascribed to this apparatus is that it may be assembled or disassembled without draining the buffer and coolant. Morever the individual tubes may be removed from the assembly during operation without similar draining of the buffer and cooling chambers. A variety of gel tube sizes can be accommodated by using interchangeable upper buffer chambers. The tubes do not rotate during operation but remain fixed in their relative positions. A similar multiple tube gel electrophoresis apparatus for handling a number of samples simultaneously is disclosed in U.S. Pat. No. 3,867,271.
In U.S. Pat. No. Re. 27,552 an apparatus for density gradient electrophoresis is described. An important feature of this apparatus is the use of electrodes immersed in electrolytes disposed near the top and the bottom of the vertical gradient tube. Semi-permeable membranes are utilized to permit ionic current flow from the electrolyte solutions to the fluid columns contained within the vertical tube while isolating such solutions from the columns.
U.S. Pat. No. 4,199,428 provides a sample feeder which can be used for sequentially delivering multiple samples to a sample applicator of an electrophoresis system.
An automatic multiple-sample applicator for a two-dimensional gel electrophoresis system is described in U.S. Pat. No. 4,061,561. The multiple-sample applicator coacts with a tank cover allowing an operator either to depress a single button thus causing multiple samples to be simultaneously deposited on the gel or to depress one or more sample applicators separately by means of a separate button for each applicator. The sample applicator picks up multiple specimens from corresponding wells in the sample holder using capillary action to fill when contact is made by the applicator with the fluid surface. The electrophoretic gel is held in a tray and the samples are transferred to the gel through the applicator tips. These tips can cut into the gel and thus they eliminate the need for prepared slot formation on the gel.
U.S. Pat. No. 4,130,471 provides a microelectrophoretic apparatus and process which employs a multi-sample applicator capable of applying 10 samples consecutively or simultaneously and is adapted to be used with the apparatus of U.S. Pat. No. 4,061,561 discussed above for two dimensional gel electrophoresis.
Alternative systems used in the art to provide continuous electrophoretic separations in an automated mode utilized moving belts or film covered with the electrophoretic medium and sample disposed on one surface and passing the belt or film through the electrophoretic chamber. Representative systems of this type of arrangement are found in U.S. Pat. No. 3,133,009 (coated tape); U.S. Pat. No. 3,896,021 (cellulose acetate coated tape); U.S. Pat. No. 4,059,501 (coated moving belt) and U.S. Pat. No. 4,198,284 (pair of endless belts carrying sample on film).